1. Field of the Invention
The present invention relates to a manpower vehicle that is moved by swinging a handle lever back and forth relative to the vehicle body.
2. Description of the Related Art
A hand-driven tricycle is known which has a front wheel and a pair of rear wheels rotatably attached to the tricycle body. This hand-driven tricycle is arranged such that driving means can forwardly rotate the front wheel or rear wheels. Since hand-driven tricycles are highly stable during traveling, attention is now being paid to them as vehicles for, in particular, people who have disabilities affecting the legs.
A handle lever as a driving mechanism for driving the front wheel or rear wheels is provided on the upper end of the handle post so that it can swing back and forth relative to the tricycle body. When the user swings the handle lever back and forth by the arms, a driving wheel is rotated through a link mechanism that transmits the swing movement to the wheel. A driven wheel is formed integral with the front wheel or rear wheels. The driving and driven wheels are connected by a chain stretched therebetween. As a result, when the handle is swung, the front wheel or rear wheels are rotated via the chain and driven wheel so that the tricycle moves forward.
Conventional hand-driven tricycles employ a link mechanism for converting the swing movement of the handle lever into rotary movement. In the link mechanism, which connects a plurality of link members so that they can rotate, the link members repeatedly pivot, contract and expand, thereby rotating the driving wheel in one direction, i.e., in the direction in which the tricycle body moves forward.
However, when the link members pivotally connected to each other shift from a straightly extended state to an oblique state, they may well be hard to pivot in a predetermined direction, or may be pivoted in the opposite direction.
Accordingly, even though the handle is swung back and forth, the tricycle may not move forward. Further, if the link members are pivoted in the opposite direction, the tricycle may move backward.
The present invention aims to provide a hand-driven tricycle that can be moved forward by swinging the handle lever, without using a link mechanism.